Impression mechanism for printing presses



July 23, 1940- B. D. STEVENS IMPRESSION MECHANISM FOR PRINTING PRESSES Filed NOV. 17, 1938 3 Sheets-Sheet l ATTORNEYS I July 23, 1940. STEVENS 2,208,688

IMPRESSION MECHANISM FOR PRINTING PRESSES 1 V5 NTOR. 541/2 5 65606715 BY $0M, p

July 23, 1940.

B. D. STEVENS IMPRESSION MECHANISM FOR PRINTING PRESSES Filed Nov. 17, 1938 3 Sheets-Sheet 5 I V IN VENT OR. fluff Z7. fi /e726 8 BY i Z fi I H z I'I TQRNEYS Patented July 23, 1940 UNITED STATES IMPRESSION LIECHANISM FOB. PRINTING RES SES

Burt D. Stevens, Golf, 111., assignor to Miehle Printing Press & Manufacturing Company, Chicago, 111., a corporation of Illinois Application November 17, 1938, Serial No. 240,922

8 Claims.

This invention relates to improvements in printing presses and it is more especially applicable to that class of presses known in the art as power plate presses which print from engraved plates to produce paper currency, security documents and the like.

In that branch of printing, the material which is to receive the'impression is of a comparatively hard texture and therefore it is necessary to 10 apply a considerable amount of pressure to the printing members in order to transfer all of the inkfrom the engraved design in the printing plate to the material to be printed.

It is evident, therefore, that "in the presses of the power plate type, the frames must be of exceedingly sturdy constructionso that they may withstand the stresses to which they are being subjected during the printing operation.

Furthermore, in order that the best printing results may be obtained, the pressure which is to be applied to the printing members should be properly distributed over the entire printing area.

One of the primary objects of my invention,

5 therefore, is to provide an improved pressure mechanism so designed that the entire force of the pressure applied between the printing elements is so taken up that no force shall be exerted on the frame itself or on any other part of the press.

Another object of the invention resides in the provision of means whereby the printing pressure can be accurately predetermined and maintained.

A further object is to provide means which will permit independent adjustment of the pressure at each end of the impression member.-

' Still further objects will be apparent from the following description and appended claims.

One preferred form of my invention is illustrated by way of example. in the accompanying drawings, in which:

Figure l is a side elevation of a power plate printing press, showing the general arrangement .of the pressure controlling means and of the mechanism whereby the pressure is transmitted to the printing elements of the press;

Figure 2 is a plan view of the parts illustrated in Figure 1; and

Figure 3 is a partial cross section of the pressure transmitting mechanism taken at right angles to the axis of the impression element.

Presses of the type to which I have applied my invention usually include, as exemplified in the drawings, a square table I!) which is preferably supported by base members such as legs It. In

the upper face of said table is provided a rectangular track which supports and guides the planks which carry the engraved printing plates and which planks are-moved from station to station to be submitted to the various operations 5 such ,as inking, wiping and impression.

The mechanism to be described merely concerns the means whereby pressure is transmitted and applied to the printing members of the press and therefore it is not deemed essential to 10 describe such devices as the inking mechanism, wiper mechanism, etc. which do not form any part of this invention. Likewise, the means for driving the parts disclosed, and which preferably is of any conventional driven gear type, also is 15 not illustrated or described.

Making reference to Figure 1 of the drawings, it will be seen that the impression roller I 2, in the art commonly termed a D-roller, is carried between upright roller frames i-3 and 13, both of 20 which are secured to the table 10 in any suitable manner. At the outside of the table I0 and bolted together withthe frame I3 is arranged a frame H, which, as will be hereinafter described, supports a large impression roller l5, see Figure 2, 25 mountedto cooperate with the roller l2 to apply pressure to the planks and printing plates thereon, as they pass between said rollers in order to effect an impression on the material to be printed.

. Preferably I utilize pneumatic power whereby 3o pressure is applied to the roller I2, although other sources of power could be used without departing from the principles of the invention. 1

The pneumatic system whereby my purpose is accomplished includes an air supply line I6 5 which shall be connected to any source' of air pressure such as a pump or the like, not shown.

Two branch lines I! and I8 lead to air pressure tanks l9 and 20 respectively. At the under vside of the table ID are mounted two air cylin- 40 ders 2i and 22, the former of which-is connected to the pressure tank l9 by the pipe 23, whereas the cylinder 22 is connected to the tank 20 by the air line 2&.

In order to control the air pressure that is to 45 be maintained within the tanks l9 and, I arrange pressure reducing valves 25 and 26 in the air lines I! and I8 respectively. Pressure gauges 21 and-28 are also incorporated in these air lines so that the pressure to be maintained 5 at either end of the impression i. e. D-roller [2 may be readily observed at any time.

Describing now the preferred arrangement of pressure transmitting mechanism as more clearly illustrated in Figures 1 and 3, it will be apparent 5 that identical mechanism is applied to both ends of the D-roller l2 and therefore in view of this duplication, it will be required to describe only that part of the mechanism provided at one end of said roller.

As shown in Figure 1, a piston 29 operates within the cylinder 22, it being forced upwardly when air pressure is admitted into said cylinder from the air line 24. To the piston 29 is pivoted a link 30, the free end of which is in turn connected to one end of a lever 3| which swings about the pivot 32. To the outer end of the lever 3| is pivoted a connecting rod 33 which, during the upward movement of the piston 29 is pulled downward. This rod extends upward through a clearance hole provided in theroller frames l3 and I4 and its upper end is threaded adjustably into a link 35 which swings and projects downwardly from a steel lever 36, see particularly Figure 3.

In this lever are inserted hardened steel pivots 31 and 38 which serve as bearing sockets for one edge of a hardened double V block 39 and a hardened steel pivot edge 40 respectively, which latter is secured within a recess in the cap 4|. The other edge of the block 39 extends into a V shaped groove formed in a hardened steel plate 42 which rests on the top of the journal bearing 43 which supports one of the D-roller journals 44.

The D-roller is urged upwardly by means of a coil spring 45, the lower end of which bears against the journal bearing 46 for the large impression roller IS. The roller frames l3 and I4, and likewise the roller frames located at the opposite ends of the rollers l2 and I5, are bolted together by means of nickel steel rods 48 and 49 which extend through appropriate caps 4| and 50.

The vertical position of the roller l 2 and therewith the gap between said roller and the roller 15 can be readily adjusted by turning the set screw 5|, the lower end of which, is hardened and bears against a hardened steel insert 52 provided in the top face of the rod 49. The vertical position of the roller l5 can also be varied by means of the adjusting screw 53 which bears against the lower face of the journal bearing 46.

In the operation of the mechanism described herein, it will be apparent that when the pressure reducing valves 25 and 26 are adjusted so that the two gauges 2'! and 28 show equal pressure, the pressure exerted on the two ends of the roller I 2 will remain equal, thereby giving equalized pressure over the entire width of said roller. However, if at any time it is found thatmore pressure is desired at one end of the roller l 2 than at the other, the pressure reducing valves can be readily adjusted to produce different pressure at each end of the roller and of course the difference of pressure will be indicated on the gauges 21 and 28.

It is also evident that with this arrangement the press frame itself will be relieved of any stress due to the impressional forces applied between the rollers I2 and I5 because the entire force of the pressure is taken up by the pair of steel rods 48 and 49 which extend through the roller frames at each end of the said rollers.

Furthermore, this manner of transmitting and applying pressure will result in the smoothest possible action because of the constant downward pull of the connecting rods 33 and associated parts due to the air pressure built up within the air cylinders and transmitted by means of the pistons therein. Moreover, because of the uninterrupted engagement between and the elimination of friction at the knife edge pivot points in the pressure transmitting mechanism, any shock will be avoided at the moment when pressure is being applied.

In impression mechanisms heretofore embodied in presses of the power plate type, the pressure was applied by the use of jack screws or the like means, which held the impression roller substantially rigid when under impression so that the roller could not yield at the moment when the printing plate entered beneath it. This resulted quite frequently in damage to the leading portion of the plate.

With the fluid pressure means, such as constitutes my invention, there shall be suflicient yield so that the above condition will be eliminated.

It will be readily understood that while I have described and illustrated one specific form of mechanism, many modifications could be adopted which would give equal results. Furthermore, the arrangement could be applied to presses other than the power plate type.

It is. therefore my intention to cover any modifications and manners of application that will come within the terms of the appended claims.

I claim:

1. In a printing press, the combination of a frame, an impression roller supported thereby, a complementary member cooperating with said roller, means for limiting the extent of movement of said roller relative to said complementary member, a source of pneumatic pressure, a lever mechanism provided at both ends of said roller for transmitting pressure from said source to said impression roller and including knife edge pivots, pressure indicating gauges, and pressure reducing valves associated with said gauges and adapted to be set so that any-desired pressure can be applied at each end of said roller.

2. In a printing press of the class defined, the combination of a pair of cooperating rotary members, pressure mechanism to actuate one of said members for imparting pressure to a printing form while passing between said members to effect an impression, the other one of said members during the printing period acting as a counter support for said printing form, said mechanism including fluid pressure means and a lever system whereby pressure is transmitted to each end of said first mentioned member, and means associated with said mechanism for independently determining the required degree of pressure to be applied to each one of said ends.

3. In a printing press of the class defined, the combination of a pair of cooperating rotary members, pressure mechanism to actuate one of said members for imparting pressure to a printing form while passing between said members to effect an impression, the other one of said members during the printing period acting as a counter support for said printing form, said mechanism including fluid pressure means and a lever system whereby pressure is transmitted to each end of said first mentioned member, and means associated with said mechanism for independent- 1y predetermining different degrees of fluid pressure to be applied to each one of said ends, the pressure being transmitted in a manner that said impression member may yield even when maximum pressure is applied.

4. In a printing press of the class defined, the combination of a pair of cooperating rotary members, pressure mechanism to actuate one of said members for imparting pressure to a printing form while passing between said members to effect an impression, the other one of said members during the printing period acting as a counter support for said printing form, said pressure mechanism including, a system of levers so arranged as to permit yielding of one of said rotary members even when under maximum pressure, and fluid actuated means for applying pressure at each end of said first mentioned member, means provided in said system of levers whereby the extent of movement of one of said rotary members towards the other can be predetermined, and means associated with said mechanism for independently determining the required degree of fluid pressure to be applied to each one of said ends.

5. In a printing press of the class defined, the combination of a pair of spaced, relatively adjustabl, rotary members between which a plank with a printing plate thereon is passed, one of said members being an impression member for imparting pressure to said plate and the other acting as a counter support for the plank while pressure is being applied during printing, pressure mechanism, including fluid actuated means for transmitting pressure to each end of said im pression member, and means for independently determining the required degree of fluid pressure to be applied at each end of said latter member, the pressure being transmitted in a manner that said impression member may yield even when maximum pressure is applied.

6. In a printing press of the class defined, the combination of a polygonal press frame for supporting a printing plate carryingplank, spaced impression members mounted for rotation in said frame, fluid pressure means associated with said members for applying pressure thereto, guide ways on said frame over which a plank is moved to pass between said members and into printing relation therewith while under pressure, means whereby the extent of pressure to be applied at each end of one of the impression members can be pre-determined, andmembers, functioning independently of said frame, to take up the entire force of transmitted pressure.

7. In a printing press of the class defined, the combination of a polygonal press frame for supporting a printing plate supporting plank, spaced impression members mounted for rotation in said frame, fluid pressure means, a lever system whereby pressure is transmitted from said means to said impression members, guide ways on said frame over which a plank is moved to pass between said members and into printing relation therewith while under pressure, means whereby the extent of pressure to be applied at each end of one of the impression members can be pre-determined, and members, functioning independently of said frame, to take up the entire force of transmitted pressure. 7

8. In a printing press of the class defined, the

' combination of a polygonal press frame for supporting a printing plate supporting plank, impression members mounted for rotation in said frame, fluid pressure means associated with said members for applying pressure thereto, spaced guide ways on said frame over which a plank is moved to pass between said members and into printing relation therewith while under pressure.

means whereby the extent of pressure to be applied at each end of one of the impression members can be. ire-determined, and members, functioning independently of said frame, to take up the entire-force of transmitted pressure, the pressure being transmitted in a manner that said impression members may yield when a plank passes therebetween.

BURT D. STEVENS. 

